How ion channels sense membrane potential

摘要

Understanding the inner workings of an ion channel has, in the last several years, boiled down to a hunt for dynamic structural cartoons that capture the essence of the channel's biophysical behavior. The main approach to this end has been the "structure-function" study in which selected residues are mutated and the functional consequences are explored electrophysiologically. Functionally important regions of the ion channel protein are often revealed from this type of experiment. Nevertheless, these studies are typically devoid of anything approaching real structural data. Therefore, the cartoon models depicting, for example, the way ion channels open and close are largely fantasies, however much insight they provide. This deficiency changed dramatically with the first crystal structure of a bacterial potassium channel. The significance of this scientific breakthrough included the sobering realization that standard structure-function studies can result in absurd structural predictions, highlighting the importance of atomic level structures to accompany functional studies.